At least 30 minutes, apparently. Any effect you feel before that is placebo. Which shouldn't be read as "not real". The placebo effect means that actual physio

At least 30 minutes, apparently. Any effect you feel before that is placebo. Which shouldn't be read as "not real". The placebo effect means that actual physiological changes are happening in your body, they have just been initiated by your PNI system rather than the the substance.